Coupling-key



H. LBECK.

COUPLINGKEY.' APPLICATION FILED 3.4, 19H5.

1,397,530, Patented Nov. 22, 1921.

. Sgm

/f/ j# /f/ WW/ j x mm m A 5513 ozmm HILDING LBECK, or nnsniwn, SWEDEN.i

Specification of Letters Eatent.

rammed Nev. 22, 1921.

Application fuea February 4, 1919. senin No. 274,991.

' To all w/tom it may concern.:

Be it known that I, HTLDING LBECK, a subject of the King of Sweden,residing at Heserud, Sweden, (at present at Biltmore Hotel, New Yorkcity, N. Y.,) have invented certain new and useful improvements inCoupling-Keys, of which the following is a specification. v

This invention relates to keys such as are commonly used for securinggears, pulleys, couplings, or similar machine parts to rotating shaftsor theY like,` so as to'corn'pel such machinepart to rotate with theshaft; Such keys ordinarily makev a rigid connection between the twoparts, which is often a disadvantage, especially in gear or Similartransmissions Where sudden speed variations may take place, or where the'resistance may be increased or reduced suddenly, as for instance in thecase of automobilesin accelerating or braking, or under the action ofsprings. The transmission parts `are thus subjected to sudden shocks"and destructive blows, which may be quite disastrous, especially to theteeth of toothed transmission ears.

It is the object of my present'` invention to provide means whereby the*disadvantages of a rigid key connection will be avoided. This isaccomplished by providing an elastic orfleXible key, that is, va keywhich can beV compressed to a certain extent and will thus act asspring.- 4Such vcompression will permit, between the shaft and the' gearor similar machinepart connected therewith, a certain amount l ofVdisplacement in the direction oppositeto 'the direction of rotation, ora torsional yielding, as itmay be'` called;- Another advan'tage of suchflexible' or `yielding keyconnection Vin' thetcase` of geartransmissions resides in the fact that the gears willadjustfthe'mse'lvesA automatically, so that the whole active toothsurfaces on the gears will come into Contact, and consequently' thepressure*willl be more equally divided and thewear vTnaterially reduced(Several examples of flexible key constructions and several forms ofusingsuch constructions have: been shown'in the accompanying drawings,but itis to' be understood that't'heconstru'ction as well as the mannerof application of flexible keysmay be Ament is als followsz variedinmany different ways, andthat I do not' wish to be limitedl bythe formsshown.

- In'these drawingsgFi'gure I is a plan view of one form of flexibleykey, showing the key in its position of rest on one of the two parts tobe coi'inectedgFig. E2 is across section taken on line 2 2 of F ig. l,but showing the keyy in position between the twoparts Figs. ilandft'sliow on a. reducedscale".V a different position of the key withrespect to the two machine parts, Fig. 3 being aisection' taken on lineS--Sof Fig. et, and Fig. 4 a section on line 4 4 of Fig. 3; Figsl, 6 and7 are views similar tol Fig. l, showing, three other forms of suitablekey construction; and Figs. 8 and 9'illustratetvwo additional forms ofusing my ei'ible key construction, Fig. 8 being a plan view similar toFigs. l and lar to Fig.

Referringofirst to Figs. l4 kto 4, A represents one ofthe connectedparts, say a shaft, provided with aY suitable socket or slot'A toreceive the key B.V This latter', ass'hOWn, represents a key of thevusual shape, but slit- -5 vto 7, and F ig, 9 being a cross sectionsimited from both ends' toward the middle portion, in the direction ofits length, so as to provide tongues B which are preferably bent outwardso 'as to normally assume the f Y position shown in Fig. l; The two?tongues on each en d of the `key Aare capable of a movement toward eachother, and in this manner the key is provided with a certain amountof'elasticity 1in a direction transverse to its length, that is,circumferentially `of the shaft The key socket or slot A is preferablymade wide enough to receive the key in its normal position, or positionof rest. With'the tongues bent outward as shown in Fig. 1, Vso that therigid central portionorl the key will, in this position" ofthe key, beout of contact with both opposing walls of the slot-A.

- The key projects beyond the socketi'A and into a slot or keyway C of agear, pulley, or like 'machine part C toI be con- 'ne'cted with theshaft A.V The slot or keyway is preferably of substantially the samewidth as the socket A', and in most cases it will extendY from one sideof the pulley orv gear C to the other,`the key being generally of a"length. correspondingtothe width of the pulley, gear or the'like to beconnected with the sha v c. y

The operation of'my flexible keyfarrange- Y With the Shaft AAat rest,thekey B willj be 4in its expanded pofsition shown in Figs; lend 2.y Inorder to explainthe operatioirfclearly, Illave indicated in Fig. 4 by anarrow the direction in which I assume the shaft to be rotated,

. and l will designate the walls of the sockets AQVC located in thisfigure on the lefthand side of the key'as the front walls, and thoselocated on the right-hand side of the key as the rear walls of thesockets. As the shaft now starts to rotate, the rear wall of the slot Awill engage the keyand tend to take it pvalong. The gear or pulley Cwill at Y first resist such movement, the front wall of theslot Cpassing against the key in a direction opposite to the direction ofrotation. 'lhe keyv will thus be compressed, the tongues B being broughttoward each other, yas shown in Figs. Sand 4. Owing to theresistance-which the key opposes to its compression, there is a certainspring action between the shaft and the part C, and the rotation .oflthe shaft will'not be communicated to the part C suddenly, with a shock,as is the case with a rigid key connection, but gradually.

After the shaft and transmission parts connectedytherewith have reachedtheir normal speed, that` is, when the load becomes normal, thepressureV on the key will be somewhat relaxed, and the latter willassume a slightly expanded position, which will Vbe intermediate betweenthe fully expanded position shown in Figs, l and. 2 and `thefullycompressed position shown in Figs. .3 andfl.` If there is a suddenchange in speed, or if the load or'resist'ance in onel of the parts issuddenlyin'creased or decreased,

the key will either be compressed or will expand, asthe case may be, andwill thus effectively prevent shocks, or atleast materiallysoften theireffect. Under ordinary Y A`In Fig. 7 lI have illustrated aforin offlexible key -made of a single piecey of metal B5, curved so .astonormally engage Vone wall Iof the key sockets or slots with vitscentral -portiomand theopposite wall with Aitsen'd working conditionsthe key would not be .fully compressed unless there is a considerableoverload Vplaced on the transmission. The compression `of the key, asdescribed above, will straighten it out and leave a narrowspace ineachrsocket, these spaces extending lengthwise of the socket'wallsopposite to those between which the key :has been compressed (seeFigs. 3andfl). Y

" Instead of `being made of one.,y piece of metal, the key shown inFigs. litod might consist suitably. of two or more pieces, securedtogetherl as by welding,lriveting or otherwise, or it might bemade ofsay elastic pieces B5 in contact with veach other at their ,end portionsand normally out of contact at their center portions, as shown in-Fig.5.

Another form of flexible keyhas been -shown in `F1ig..(i',fin which vtwokey portions :B4 are normally held apart by spiral' sprmgs D r.engagingsuitable .sockets-provided in the inner faces of said key portions. i

Vkeys of standard sizes.

portions. When compressed from both sides, the key will tend to becomestraight,

that the flexibility may be varied, not only by using keys of differentstrengths and different degrees of elasticity, but in other ways, suchas for instance by placing in a slot of a given length, instead of onekey,

as shown in Figs. l to V7, two or Vmore shorter keys arranged end to endin the slot, as shown in Fig. 8. This will of course give a strongerspring action than if one key only is employed.

. Another way -of obtaining various grades 1 of spring action;fordiflerent load requirements isto provide two onmore' keyv slotson-the circumference of the shaft, as shown `for example' in Fig. 9.Still another-way to obtain this result Vwould be to make keys of thesame-dimensions, but of different degrees of hardness or flexibility. Bya suitable `combination of the above-mentioned alternatives it willbe'possible to obtain for any. case .the desired flexibility. f

Various modification may be made without departing from the nature of myinvention as set forth in the appendedclaims. f l claim as myinvention.:

Vl. Al one-.piece key fortransmittingfmo- Vtion from one rotaryfpart toanother,ppro.

vided with'a rigid central portion andintegrallongitudinally-splittransversely elastic end portions. Y'

a 2. A structure comprising -twofparts rortating about the same axisvandzprovlded 1n their adjoining surfaceswith corresponding sockets, akey having a portion movable-elasticallyiin a direction transverseto thelength ofthe key, and a rigid portion, the width-` ,of which is .smaller'than that of the sockets.

3. A structure comprising twopar'tsrrotating about the same axis,and'afflexible'key engaging both f parts to .normally "compel .them tomove in unison, but allowing a slight movement of one part relativelytothe other in the case 'of a sudden variation of speed orresistance inVone-ofthe parts,`said key, when fully compressed, forming ofitself (ato the other. v

4,. A structure comprising two Aparts ro- .,tating `about thesameaxis'and provided, in

their adjoining surfaces, with correspondin sockets A`forrnlng asinglejkey-way-thelength lrigid bodyV insuring direct `and positivetransmission of rotary movementof onepart of which is parallel to theaxis of rotation, and a plurality of circumferentially-yielding keyslitted in thesingle key-way and arranged to be simultaneously anduniformly compressed incident to relative movement of the two parts.

5. A structure comprising twol parts ro tating about the same axis, anda flexible key engaging both parts to normally compel them to move inunison, but allowing a slight movement of one part relatively to theother in case of a sudden variation of speed or resistance in one of thetwo parts, said key having fiat faces adapted, upon complete compressionof the key, to be brought into facial abutment thereby forming a rigidbody insuring direct and positive transmission ol rotary movement of onepart to the other part.

6. A structure comprising two parts rotating about the same axis, one ofsaid parts having a socket parallel to the axis of rotation, and a keyconnected with the other part and having a portion projecting into saidsocket, said key being elastic and curved lengthwise of the socket, andhaving a tendency to straighten out while transmitting power. A

7. A structure comprising two parts rotating about the'same axis, one ofsaid parts having a socket, a key connected with the other' part andhaving a portion projecting into said socket, said key being elasticcirc'umferentially of said parts and occupying, during the normaltransmission of power, a position intermediate between its fully relaxedand fully stressed positions, whereby during normal transmission ofpower said key may either increase or decrease its state of elastictension according as the driving pressure or resistance increases ordecreases.

In testimon whereof I aix my signature in presence o two witnesses.

HILDING LBECK.

`l'lVitnesses: e

ALBERT E. PARKER, b. L. WHITMAN.

